Why you should care

When Melissa Graham gets dressed in the morning, she always puts on a pair of fresh white socks. But it’s not a fashion choice. If her foot temperature rises, the sock fibers send an alert to her phone, prompting her to check out her extremities. Graham has diabetes, and these socks could save her life.

A rise in foot temperature sounds innocent, but for diabetics it can be a precursor to ulcers, which all too often result in a foot or leg amputation. And that loss of a body part can prove deadly. According to a 2013 study conducted by the European Society for Vascular Surgery:

Up to 50 percent of diabetics die within two years of a foot or leg amputation.

That news is especially concerning given the high number of amputations performed each year, even though it’s difficult to confirm figures due to a lack of standard definitions for amputation and diabetes diagnosis, as well as a variance in study design and methodology.

A 2005 study conducted by the University of Manchester and the Swedish Institute for Health Economics, for example, estimated that worldwide a limb was amputated every 20 seconds as a direct result of diabetes, which adds up to more than a million amputations per year. On the other hand, a 2016 European study found that one amputation every seven minutes was directly attributed to the disease in countries monitored by the Organization for Economic Cooperation and Development. That means an annual total of more than 75,000 diabetic amputations. But in 2014, the Centers for Disease Control and Prevention reported 108,000 diabetes-related amputations in the U.S. alone.

While current amputation rates cannot be confirmed, the number of wounds related to diabetes has increased due to inadequate patient monitoring during the healing process, says Dr. David Armstrong, professor of clinical surgery at the Keck School of Medicine of the University of Southern California and one of the authors of the 2005 study. Shortly after diagnosis, people with diabetes frequently develop peripheral neuropathy — that is, they lose the ability to feel pain in their extremities. Because feet are farthest from the central nervous system, they tend to develop neuropathy first, explains Armstrong, leading to ulcers and open wounds. “I recently had a patient who’d been walking around on a nail for several days and didn’t realize it,” Armstrong says.

Pain is the body’s first line of defense when it comes to identifying and treating injuries. Without pain, it becomes easier to disassociate from the wound and put off treatment, increasing the risk of infection. Diabetics are also at risk of peripheral artery disease, which can make an infection lethal. Sometimes, amputating the foot or leg is the only way to save a patient’s life.

Still, amputation does not guarantee a clean bill of health for diabetics. The rate of death is elevated among diabetic amputees because many have significant end-stage illnesses like cardiovascular disease. Limiting mobility further can make them more susceptible to stroke or heart attack. “Sometimes they don’t even get out of bed after amputation,” Armstrong says. “They’re like modern-day lepers.”

The future of health care [is in] things that monitor your body continuously and fit into objects you already own.

Ran Ma, founder, Siren

The key to preventing these amputations is proper monitoring. Physicians recommend that diabetics check their feet every day. If they notice anything irregular, they should go to their doctor for a manual temperature check. For many, this is an unrealistic goal.

But tech advances are making it easier for at-risk diabetics to remain vigilant. Melissa Graham’s smart socks were created by Siren, a health technology company founded by biomedical engineer Ran Ma. Microsensors woven into the fabric continuously monitor the feet and ping the patient’s phone if an increase in surface temperature is detected. Ma developed the socks as part of her mission to make more-seamless medical wearables. “The future of health care [is in] things that monitor your body continuously and fit into objects you already own,” says Ma.

Since wearing the socks, Graham is less worried she’ll develop a foot ulcer that will lead to infection, amputation … or worse. “I forget to check my feet most days,” Graham says. “But I can look on the Siren app to see if there are any potential risks and visually evaluate them later.”

To decrease diabetic foot wounds and amputations, the first step is to decrease the number of people who develop diabetes in the first place. Currently, 100 million Americans have prediabetes or diabetes, but that number is going down, according to Armstrong. “If we get people to do 20 minutes of exercise a day, three to four days a week,” he says, “we can reduce the rate of conversion from prediabetes to diabetes by nearly 60 percent.”

Correction: An earlier version of this article mistakenly calculated the number of amputations per minute.